The qanats of Xinjiang:historical development, characteristics and modern implications for environmental protection

In China,qanats(kan’erjing/karez)exist only in Xinjiang Uygur autonomous region,being one form of traditional irrigation technology that made great contributions to oasis civilizations.There are different opinions on the origin and date of the qanats in Xinjiang due to a lack of adequate evidences.And uncontrolled over-exploitation of groundwater by pumping wells,as well as the expansion of surface water interventions nowadays,has caused serious impacts on not only the qanats,but also local ecological environments.There exist long-time arguments on whether the qanats should be restored or preserved.This study aimed to examine the historical development, geological conditions and characteristics,and modern implications of the qanats for oasis environmental protection, and to discuss the initiatives taken by local governments.The whole Xinjiang Uygur autonomous region was included as the study area,with a specific focus on Turpan prefecture.The materials and data were obtained from literature review and governmental documentation.Based on a systematic examination of three prevailing theories on the origination of Xinjiang’s qanats,it is suggested modern archaeological techniques could be good solutions to explore the origination in addition to historical records used normally.Although qanats fail to fully meet today’s enormous water demands,their rich historical,cultural,ecological and environmental implications in arid areas should not be underestimated.As a cultural heritage and ecologically-friendly engineering creation,qanat systems shall be kept in good condition and function by a valuable number.Recent initiatives to protect and restore target qanat systems in Xinjiang could provide positive examples for the practices in other regions of the world where the protection and restoration of qanats or similar technologies are desired.